The families described the report as "honest" but said its remit was drawn so tightly that it could not point blame at those in command. One of the parents compared the military investigation to the Butler and Hutton inquiries on Iraq. "It is a catalogue of disasters - one mistake after another. Concerns about ammunition were passed up the chain of command, and they were dismissed. That is a scandal," said Mike Aston.

Cpl Aston's mother, Glenice, who was close to tears, said that her son had warned that he could be killed on duty. "He was a soldier, and he said to me: 'It happens mum'," she said. "That is the way he was but it doesn't make it any easier for parents and wives at home."

With the other grieving parents, Mr and Mrs Aston, from South Derbyshire, praised Geoff Hoon, the Defence Secretary, for his care in briefing them at the MoD on the report.

Tony Hamilton-Jewell expressed relief that his brother, Sgt Hamilton-Jewell, who led the patrol, was not singled out for blame in the report. There had been leaks to suggest that some senior officers were seeking to lay the blame on Sgt Hamilton-Jewell.

The inquiry, which took evidence from 113 witnesses, was told that the unit of six RMPs had gone on patrol on 24 June, 2003, to the al-Majarr al-Kabir police station in the British-controlled Basra area. Two separate units of Parachute Regiment troops who were unaware that the RMPs were in the police station, had pushed into the town to carry out searches for weapons and were set upon by a mob. The paratroopers had to fight their way out. A Chinook helicopter used to try to rescue the paras came under such heavy fire that seven people on board were hit.

It was only when an Iraqi doctor told a local unit that six bodies were in the police station that commanders realised the RMPs were there. It is believed the heavily-armed mob killed two of the men in the yard and killed the remaining four inside the police station after their ammunition ran out.

They had gone on patrol without satellite telephones, and with only 50 rounds of ammunition each. An order that troops should be issued with 150 rounds did not reach the Military Police.

The report said: "It is impossible to state categorically that their fate would have been different if they had carried more ammunition or if communications had been better."

Mr Keys said: "If they had given forethought to the risk in that town, forethought to supply of ammunition that was given to the men, and had there been a little bit more forethought that day from the paras who had been asked not to proceed with their patrol because they would be fired on and which exacerbated the situation, these boys would have been alive today. All we want is accountability."

The Iraqi authorities are carrying out a criminal investigation but Mr Keys said: "The killers' names have been handed to people but realistically whether it will go to court in Iraq is unlikely."